Apparatus for projecting lenticular film



Nbv. 23, 1937 J. EGGERT EI AL APPARATUS you PROJECTING LENTICULAR FILM Filed Nov. 24.1954

by Fa Patented Nov.

aromas a srrmrns Fort PROJECTING LEN'I'ICULAR John Eggert, Leiplig-Golilis, and Gen! Heymcr, rerun Kreis Bitterfeld, Germany, assignors to Farbenindiistrle Alrtiengesellscliaft p Frankfort-on-the -Main, Germany Application November 24, 1934, Serial No. 754,858. I In Germany November 25, 1983 z'cisimscita-ici) Our present invention relatesto projection of lenticular film.

One of its objects is an apparatus for project- .advantages described and without. additional optical devices in the path of the rays, a correctly ing lenticular film. Further objects will be seen from the detailed specification following hereafter. Reference is made to the accompanying drawing in which' Fig. 1 shows an arrangement according to this invention,

Fig. 2 shows an arrangement for obtaining for projecting uniform illumination of the picture field,

Fig. 3 shows an arrangement for projecting 'a .laterally inverted print according to this invention and Fig. 4: shows an arrangement for raising and lowering the picture during projection. It has been proposed to print on another lenticular film a lenticular film which has been ex- I posed behind a three-color filter, the embossed surfaces of the films being in contact with each other during the printinghad led to the observation that the filtermiddle lines, that is to say the lines connecting the. middle of the filter image behind each lenticul'ar element with the middle of the coordinate lenticular element with the images of this middle behind the lenticular embossing of the film, no longer intersect on the embossed side but on the'emulsion side of thefilm, so that the point of intersection is at the same distance behind the film as it was during the original exposure. Asto the extension of the deflected in view of the differing indicesof refraction of the film material and air. It has been.

I a manner that also in the projection of the copy the filter middle lines intersect onthe embossed side of the film. Operationwith such compensa-' tion lenses is however, inconvenient. Moreover, these lenses have the drawback that they distort the path of the rays, and therefore give rise to a considerable number of faultypictures, because these lenses generally have a very short focal length and therefore must be very thick in order to fulfill their purpose. This'is' particularly the in operation with sub-standard films. In

always used. Now if a copy isto be made from such a filin and if it is desired that the filter shall mirrors which are silvered on the reverse side give double contours. The. mirror or the reversal to remain in the same position as it had duringthe exposure, the compensation lens must- 5 middle groups.

case a filter-distance of about 40 was t have s focal length of 26 mm. which is impracticable. By the present invention while avoiding the discolored projection of a lenticular copy is obtained in which the filter middle lines intersect on the emulsion, side of the film. For this purpose the.

' the film at a distancefrom the film corre p nding with-the distance of the original exposure filter or its virtual image.

In Fig. 1 C is the copy made from a lenticular original film taken in the usual manner with the lenticulated side facing the multi-color filter by printing this film with its lenticulated side-in contact with the lenticulated side of the film c, the filter middle lines thereof intersecting at D. at a distance a from the emulsion side of the film C. The projection filter is placed at E at such a distance in front of the projection objective O that the objective produces at D a real 2 image of the projection filter on the emulsion side of the F is the focus of the projection objective. The distance-"of the projection filter from the. objective is greater than the focal length of the latter.

In order to obtain a sufficiently uniform illumination of the .picture field when the projection filter has the position required by this invention, it is preferable to use .a projection filter whose simple sequence of color strips is repeated comwhose front focal point lies' at F. Beyond this point F there is arranged the filter 8 whose sim-. ple sequence of color strips is repeated. Adja-. cent the middle group r, g, b there'is the group 1-,

g' b on one side and on the other side the group 1', of, b". Adjacent to these groups, .there are ,the groups 12", a' following 1" and on the other side r""',' 17"" as iifincomplete repetition of the The distance of the filter corresponds with that of the filter E inFig. 1.

As the copy, as compared with the original, is laterally inverted, for correct projection a mirror or a reversal prism must be arranged in the path of the rays. It is preferable to use superficially silvered mirrors because the ordinary lpletely or incompletely one or more times. This is shown in Fig. 2. Referring to this figure, L is the lenticular film, O is the projection objectiveprism can be fitted either between the filter and the objective or between the filter and the screen; in the first case the color strip sequence of the filter must be reversed. The mirror is advantageously united with the projection filter to form one structural unit.

Fig. 3 shows an arrangement wherein the picture is projected so that a correct reproduction of the sides of the picture is obtained. By inserting the mirror P having its reflecting surface on the side which faces the objective the real focal point F is virtually displaced at F. The filter S having a middle group of strips 1', g and b and lateral groups of strips-must have the reversed succession of the color strips as shown in Fig. 2 because this succession is reversed by the mirror P. The reversion of the color strips is not necessary if the mirror P is arranged as indicated in Fig. 2.

The filter and the mirror can be fixed either on the housing of the projector or on the objective carrier. Finally, the filter may be arranged adjustably in a frame placed at right angles to the direction of the lenticular embossings, in order that the color of the picture may easily be altered.

In Fig. 4 there is shown, for example, such an arrangement 0 isthe objective. On the bordering edge of the front side of the objective there is mounted a pin R. Over this pin there may be fitted a sleeve Uwith the'aid of a bayonetcatch. 0n the sleeve U there are mounted by means of the member A the pieces of sheet metal B and C which carry the mirror P arranged at an angle of 45 to the optical axis in front of the multi-color filter S arranged on the piece of sheet metal A. The multi-color filter can be moved in direction perpendicularly to the optical axis as is indicated in Fig. 4 of the drawing. The mirror P projects the picture produced by the objective 40 Q on the projection screen.

What we claim is:

1. In an apparatus for projecting lenticular film in combination, a lenticular film in a plane position, a projection objective in front of the lenticulated side of said lenticular film, a multicolor filter arranged in front and beyond'the focus of said objective with its color st-rips parallel to the lenticular elements, said objective and said multi-color filter being arranged at distances from said lenticular film was to project in cooperation a real image of said multi-color filterv opposite the emulsion side of said lenticular film with the images projected by the single lenticular elements in register with the like parts of the color filter record of the lenticular film, and simultaneously to project said film.

"2. In an apparatus for projecting lenticular film in combination a positive lenticular film in a plane position having a record of a multi-color filter, a projection objective in front of the lenticulated side of said lenticular film, a multicolor filter having adjacent to the central sequence of color strips lateral color strips following each other in the succession of the central color strips, said multi-color filter being arranged in front and beyond the focus of said objective with its color strips parallel to the lenticular elements of said film, said objective and said multi-color filter being arranged at distances from said lenticular film so as to project in cooperation a real image of said multi-color filter on the emulsion side of said lenticular film and with the images projected by the single lenticular elements in register with the like parts of the color filter record of the lenticular film, and simultaneously to project said film, and means beyond the objective for inverting the picture projected by said objective.

JOHN EGGERT. GERD HEYMER. 

